Montana Climate Assessment

Montana already has felt the effects of a changing climate and will continue to feel further impacts in the coming decades, according to a new, scientific assessment that looks at past climate trends and how they are projected to change in the future.

“The central goal of this effort was to create a product that would be useful to Montanans in planning for and adapting to a changing climate,” said lead author Cathy Whitlock, a professor of earth sciences and fellow of the Institute on Ecosystems at MSU. “The assessment’s findings foresee a hotter future for Montana, but it is the specific details about what this means that we hope citizens will find useful.”

“For years stakeholders across the state have wondered how much Montana’s climate has changed and how much will it change in the future,” said Kelsey Jencso, director of the Montana Climate Office at the University of Montana. “The science to address this question has previously been performed at regional or national levels, and this assessment provides a first look at these trends and their impacts at a local level.”

Some of the key findings include:

The number of days when temperatures exceed 90 degrees and the number of frost-free days are expected to increase. Increases in days above 90 degrees are expected to be greatest in the eastern part of the state.

Montana’s snowpack has declined since the 1930s in mountains east and west of the Continental Divide. This decline has been most pronounced since the 1980s. Warming temperatures over the next century, especially during springtime, are likely to reduce snowpack at middle and lower elevations.

Decreasing mountain snowpack will continue to lead to decreased streamflow and less reliable irrigation capacity during the late growing season.

Montana’s growing season is lengthening – now 12 days longer than it was in 1950.

More frost-free days and longer growing seasons may enable greater crop diversity. However, more 90-degree-plus days also will increase water loss via evaporation and transpiration from plants. In addition, hotter days will increase water demand for most crops, limit grain development and increase heat stress on livestock.

Forest fires will be bigger, more frequent and more severe in the coming century.

The report is the product of a two-year effort by university researchers and students, state and federal researchers, nonprofit organizations, tribal colleges and citizens across the state.

“The Montana Climate Assessment offers the ranching community valuable insight into recent and future climate variability,” said Errol Rice, executive vice president of the Montana Stockgrowers Association. “This information will allow ranchers to better mitigate against weather-related risk factors, now and into the future.”

The full assessment is available at montanaclimate.org, along with a schedule of town hall meetings to be hosted by the authors this year across the state.